Client Credentials Grant

Machine-to-machine (M2M) authentication for confidential clients (RFC 6749 §4.4). Client authentication (client_secret_basic or RFC 7523 private_key_jwt) and access-token protection (Bearer or RFC 9449 DPoP) are independent choices exposed in one executable flow.

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Machine-to-Machine

Sequence Diagram

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ClientAuth ServerAPI1Prepare Token Request2Access Token Response3API Request
Request
Response
Redirect
Internal

Step-by-Step Breakdown

1
Prepare Token Request
ClientAuthorization Server
2
Access Token Response
Authorization ServerClient
3
API Request
ClientResource Server

Token Inspector

Specs for this flow

Sections of the protocol that normatively define this flow, plus the security considerations that apply to it.